060f24e310
Currently the code to translate host side addresses and ports to guest side addresses and ports, and vice versa, is scattered across the TCP code. This includes both port redirection as controlled by the -t and -T options, and our special case NAT controlled by the --no-map-gw option. Gather this logic into fwd_nat_from_*() functions for each input interface in fwd.c which take protocol and address information for the initiating side and generates the pif and address information for the forwarded side. This performs any NAT or port forwarding needed. We create a flow_target() helper which applies those forwarding functions as needed to automatically move a flow from INI to TGT state. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright Red Hat
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* Author: Stefano Brivio <sbrivio@redhat.com>
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* Author: David Gibson <david@gibson.dropbear.id.au>
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*/
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#ifndef FWD_H
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#define FWD_H
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struct flowside;
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/* Number of ports for both TCP and UDP */
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#define NUM_PORTS (1U << 16)
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enum fwd_ports_mode {
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FWD_UNSET = 0,
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FWD_SPEC = 1,
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FWD_NONE,
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FWD_AUTO,
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FWD_ALL,
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};
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#define PORT_BITMAP_SIZE DIV_ROUND_UP(NUM_PORTS, 8)
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/**
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* fwd_ports - Describes port forwarding for one protocol and direction
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* @mode: Overall forwarding mode (all, none, auto, specific ports)
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* @scan4: /proc/net fd to scan for IPv4 ports when in AUTO mode
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* @scan6: /proc/net fd to scan for IPv6 ports when in AUTO mode
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* @map: Bitmap describing which ports are forwarded
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* @delta: Offset between the original destination and mapped port number
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*/
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struct fwd_ports {
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enum fwd_ports_mode mode;
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int scan4;
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int scan6;
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uint8_t map[PORT_BITMAP_SIZE];
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in_port_t delta[NUM_PORTS];
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};
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void fwd_scan_ports_tcp(struct fwd_ports *fwd, const struct fwd_ports *rev);
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void fwd_scan_ports_udp(struct fwd_ports *fwd, const struct fwd_ports *rev,
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const struct fwd_ports *tcp_fwd,
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const struct fwd_ports *tcp_rev);
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void fwd_scan_ports_init(struct ctx *c);
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uint8_t fwd_nat_from_tap(const struct ctx *c, uint8_t proto,
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const struct flowside *ini, struct flowside *tgt);
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uint8_t fwd_nat_from_splice(const struct ctx *c, uint8_t proto,
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const struct flowside *ini, struct flowside *tgt);
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uint8_t fwd_nat_from_host(const struct ctx *c, uint8_t proto,
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const struct flowside *ini, struct flowside *tgt);
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#endif /* FWD_H */
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